The present invention relates to a camera provided with a photometry device.
Recently, cameras are provided with photometry devices for automatic exposure control. In particular, as a photometry device provided in a camera, a reflection type photometry device is widely used. The reflection type photometry device is constructed to receive light reflected by an object through an observation optical system of a camera, and measure an amount of light using a photo-sensitive element to detect brightness of the object. Based on thus detected brightness of the object, an exposure value (commonly known as an Ev value) is determined, and then, in accordance with a predetermined algorithm, exposure parameters (i.e., a shutter speed and an aperture value) are determined. This type of photometry device, however, does not detect reflectance of an object, and therefore, the exposure value, and thus, the exposure control parameters are calculated on assumption that the light reflectance is a predetermined fixed value, for example, 18%.
Therefore, when an object is a whitish subject whose light reflectance is greater than 18%, the brightness is detected to be higher than its actual brightness, and accordingly, such an object tends to be photographed in underexposed condition. When an object is a dark object whose light reflectance is lower than 18%, the brightness thereof is detected to be lower than the actual brightness, and accordingly, such an object tends to be photographed in an overexposed condition.
In order to avoid the above defects, a camera provided with an exposure correcting unit has been known. In such a camera, a photographer can modify the exposure value so that photographing is performed in a slightly overexposed condition when a whitish object is to be photographed, and for a dark object, the photographer can modify the exposure value so that photographing is performed in a slightly underexposed condition. By performing such an exposure operation with modifying the exposure value, the above-mentioned problems can be suppressed.
However, differences in the light reflectance of the object also occurs due to differences in the color of the object. For example, a yellow object, whose light reflectance is relatively high, tends to be photographed in a slightly underexposed condition, and a blue object, whose light reflectance is relatively low, tends to be photographed in a slightly overexposed condition.
Accordingly, in order to execute exposure correction taking differences in the color of the object into account, the photographer is required to recognize a relationship between the color and light reflectance of the object to optimize the exposure value using the exposure correction unit. However, it is practically impossible to require photographers to perform such exposure correction. Further, if such a correction operation is required, cameras become unsuitable for automatic photographing.